Possible Interaction: Riboflavin and Tryptophan

“From experiments with solutions of riboflavin, tryptophan or HEPES, as well as combinations thereof, it is concluded that riboflavin mediates the photooxidation of either tryptophan or HEPES, resulting in the generation of H 2 O 2 .”

“This geometry and the proximity of other tryptophans explain the fluorescent quenching observed when riboflavin binds to the protein.”

“Irradiation of salt solution of riboflavin and tryptophan or riboflavin and tyrosine, resulted in cell killing.”

“The study … that tryptophan … riboflavin may act as tracer molecules for syneresis, but this was not shown for vitamin A. The evolution of tryptophan and riboflavin fluorescence … followed a first-order reaction and had strong relationships with curd moisture and whey total solids content (r=0.86-0.96).”

“…,tryptophan , and their … of riboflavin by electron transfer from the tyrosine and tryptophan moieties followed by a fast protonation of the resulting riboflavin anion rather than by … monitored by time-resolved transient absorption spectroscopy as a decay of triplet riboflavin followed by a rise in riboflavin anion radical absorption.”

“Both the presence of riboflavin and the exposure of the solutions to light alter brain concentrations of tryptophan in the developing gerbil indicating differing availability to the brain of this serotonin precursor.”

“Toxic products are formed when tryptophan is irradiated with light in the presence of photosensitizers such as riboflavin.”

“ Tryptophan enhances riboflavin-induced phototoxicity, whereas tyrosine diminishes this effect.”

“Moreover, the replacement of these tryptophan residues significantly reduced the phosphatase activity for FMN.”

“Studies in animals have suggested that the products of the irradiation of tryptophan in the presence of riboflavin may play a role in the development of hepatic dysfunction during parenteral nutrition.”

“Decreases in concentrations of methionine, proline, tryptophan , and tyrosine were significantly greater in the presence of riboflavin that in its absence.”